Abstract/Summary Now in its 15th year, The UCSF Microbial Pathogenesis and Host Defense (MPHD) program provides a comprehensive, world-class training plan to prepare graduate students and postdoctoral fellows for future careers in academics, industry, public health, or teaching. Rapid scientific advances in microbiology and infectious disease have provided unprecedented opportunities to improve the health of mankind worldwide. The importance of training our next generation of scientific leaders to use these tools for innovative approaches has never been greater. UCSF hosts an unusual number of world-class laboratories in microbiome research and each aspect of microbial pathogenesis, including bacterial, viral, fungal, parasitic, innate immunity, and systems biology research programs. The faculty has an outstanding track record of creative and high-profile research, superb mentoring, and robust research funding, and thus attracts outstanding trainees. The MPHD program has catalyzed new scientific directions and broadened the training opportunities in microbial pathogenesis by bringing together laboratories with traditional expertise in the field with those from diverse scientific fields to create an integrative program focused on issues in host-microbe interactions. The MPHD Program is open to all UCSF graduate students and postdoctoral fellows, an elite pool of very highly qualified trainees, who express an interest in microbial pathogenesis. The program integrates students, postdoctoral fellows, and faculty from diverse programs, expertise, and backgrounds by nourishing synergistic interactions and facilitating new approaches not otherwise possible. Outstanding institutional core facilities are available to accelerate application of new and emerging technologies. The program is comprised of the following program-specific components: (i) a weekly seminar series comprised of ~15 outside invited speakers as well as trainee research-in-progress talks, (ii) a yearly Bay Area-wide Microbial Pathogenesis (BAMPS) symposium now in its 22nd year, (iii) 2 revamped graduate student elective courses that provide a comprehensive curriculum in Molecular Mechanisms of Microbial Pathogenesis, (iv) a new individualized postdoctoral mentoring program that augments the already high caliber of postdoctoral training by matching fellows with a secondary mentor other than their PI, and (v) a biennial internal trainee retreat. The program has an outstanding track record: Of the 32 predoctoral trainees supported over the past 14 years, 23 are women, 11 are URM, 27 received their PhD (1 left with a Master?s degree), only 1 has opted out of a research-related career, and 4 are still in training. Of the 34 postdoctoral fellows supported, 20 are women, 10 are URM, and 100% of the trainees who have completed the program are pursuing research-related careers. We request continuation of 4 pre-doctoral slots and 2 post-doctoral slots which will allow us to continue our history of training the next generation of leaders in microbial biology who will elucidate the role of microbes in health and disease and reduce the worldwide burden of microbial pathogenesis.